# Copyright (c) 2016 Thomas Nicholson <tnnich@googlemail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The names of the author(s) may not be used to endorse or promote
#    products derived from this software without specific prior written
#    permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

import os
import time

from twisted.python import log

from cowrie.core import ttylog
from cowrie.core.config import CowrieConfig
from cowrie.ssh_proxy.protocols import base_protocol


class Term(base_protocol.BaseProtocol):
    def __init__(self, uuid, chan_name, ssh, channelId):
        super(Term, self).__init__(uuid, chan_name, ssh)

        self.command = b''
        self.pointer = 0
        self.tabPress = False
        self.upArrow = False

        self.transportId = ssh.server.transportId
        self.channelId = channelId

        self.startTime = time.time()
        self.ttylogPath = CowrieConfig().get('honeypot', 'ttylog_path')
        self.ttylogEnabled = CowrieConfig().getboolean('honeypot', 'ttylog', fallback=True)
        self.ttylogSize = 0

        if self.ttylogEnabled:
            self.ttylogFile = \
                '{0}/{1}-{2}-{3}i.log'.format(self.ttylogPath, time.strftime('%Y%m%d-%H%M%S'), uuid, self.channelId)
            ttylog.ttylog_open(self.ttylogFile, self.startTime)

    def channel_closed(self):
        if self.ttylogEnabled:
            ttylog.ttylog_close(self.ttylogFile, time.time())
            shasum = ttylog.ttylog_inputhash(self.ttylogFile)
            shasumfile = os.path.join(self.ttylogPath, shasum)

            if os.path.exists(shasumfile):
                duplicate = True
                os.remove(self.ttylogFile)
            else:
                duplicate = False
                os.rename(self.ttylogFile, shasumfile)
                umask = os.umask(0)
                os.umask(umask)
                os.chmod(shasumfile, 0o666 & ~umask)

            log.msg(eventid='cowrie.log.closed',
                    format='Closing TTY Log: %(ttylog)s after %(duration)d seconds',
                    ttylog=shasumfile,
                    size=self.ttylogSize,
                    shasum=shasum,
                    duplicate=duplicate,
                    duration=time.time() - self.startTime)

    def parse_packet(self, parent, payload):
        self.data = payload

        if parent == '[SERVER]':
            while len(self.data) > 0:
                # If Tab Pressed
                if self.data[:1] == b'\x09':
                    self.tabPress = True
                    self.data = self.data[1:]
                # If Backspace Pressed
                elif self.data[:1] == b'\x7f' or self.data[:1] == b'\x08':
                    if self.pointer > 0:
                        self.command = self.command[:self.pointer - 1] + self.command[self.pointer:]
                        self.pointer -= 1
                    self.data = self.data[1:]
                # If enter or ctrl+c or newline
                elif self.data[:1] == b'\x0d' or self.data[:1] == b'\x03' or self.data[:1] == b'\x0a':
                    if self.data[:1] == b'\x03':
                        self.command += b'^C'

                    self.data = self.data[1:]
                    if self.command != b'':
                        log.msg(eventid='cowrie.command.input',
                                input=self.command.decode('ascii'),
                                format='CMD: %(input)s')

                    self.command = b''
                    self.pointer = 0
                # If Home Pressed
                elif self.data[:3] == b'\x1b\x4f\x48':
                    self.pointer = 0
                    self.data = self.data[3:]
                # If End Pressed
                elif self.data[:3] == b'\x1b\x4f\x46':
                    self.pointer = len(self.command)
                    self.data = self.data[3:]
                # If Right Pressed
                elif self.data[:3] == b'\x1b\x5b\x43':
                    if self.pointer != len(self.command):
                        self.pointer += 1
                    self.data = self.data[3:]
                # If Left Pressed
                elif self.data[:3] == b'\x1b\x5b\x44':
                    if self.pointer != 0:
                        self.pointer -= 1
                    self.data = self.data[3:]
                # If up or down arrow
                elif self.data[:3] == b'\x1b\x5b\x41' or self.data[:3] == b'\x1b\x5b\x42':
                    self.upArrow = True
                    self.data = self.data[3:]
                else:
                    self.command = self.command[:self.pointer] + self.data[:1] + self.command[self.pointer:]
                    self.pointer += 1
                    self.data = self.data[1:]

            if self.ttylogEnabled:
                self.ttylogSize += len(payload)
                ttylog.ttylog_write(self.ttylogFile, len(payload), ttylog.TYPE_OUTPUT, time.time(), payload)

        elif parent == '[CLIENT]':
            if self.tabPress:
                if not self.data.startswith(b'\x0d'):
                    if self.data != b'\x07':
                        self.command = self.command + self.data
                self.tabPress = False

            if self.upArrow:
                while len(self.data) != 0:
                    # Backspace
                    if self.data[:1] == b'\x08':
                        self.command = self.command[:-1]
                        self.pointer -= 1
                        self.data = self.data[1:]
                    # ESC[K - Clear Line
                    elif self.data[:3] == b'\x1b\x5b\x4b':
                        self.command = self.command[:self.pointer]
                        self.data = self.data[3:]
                    elif self.data[:1] == b'\x0d':
                        self.pointer = 0
                        self.data = self.data[1:]
                    # Right Arrow
                    elif self.data[:3] == b'\x1b\x5b\x43':
                        self.pointer += 1
                        self.data = self.data[3:]
                    elif self.data[:2] == b'\x1b\x5b' and self.data[3] == b'\x50':
                        self.data = self.data[4:]
                    # Needed?!
                    elif self.data[:1] != b'\x07' and self.data[:1] != b'\x0d':
                        self.command = self.command[:self.pointer] + self.data[:1] + self.command[self.pointer:]
                        self.pointer += 1
                        self.data = self.data[1:]
                    else:
                        self.pointer += 1
                        self.data = self.data[1:]

                self.upArrow = False

            if self.ttylogEnabled:
                self.ttylogSize += len(payload)
                ttylog.ttylog_write(self.ttylogFile, len(payload), ttylog.TYPE_INPUT, time.time(), payload)
